With increasing development of a personal computer, more peripheral devices are prerequisites for enhancing functions of the personal computer. In order to expand flexibility of using such peripheral devices and avoid inconvenience and troublesome of wire linkage, various wireless transmission technologies were used to transmit data between the computer and its peripheral devices. For example, a bluetooth network is a new trend to provide localized sensitive information between a personal computer and the peripheral devices thereof. The bluetooth technology is a well known technique, which is generally used in portable communication such as cell phones or personal digital assistants (PDAs), and will not be described in detail herein.
FIG. 1 is a functional block diagram illustrating a conventional wireless transmission system by means of a bluetooth technology. The wireless transmission system comprises a computer 11, a universal serial bus (USB) 12, a receiver 13 and a peripheral device 14. The computer 11 is electrically connected to the receiver 13 via the USB 12. The peripheral device 14, e.g. a mouse, a keyboard, a scanner or a printer, has therein a transmitter 140. The transmitter 140 and the receiver 13 perform the cordless exchange of data with each other by means of a bluetooth standard. Since the peripheral devices having bluetooth modules are costly, it is not popular for common users. In addition to the bluetooth module, the cost of other wireless transmission modules, so far, are also unacceptable by most people.